It seems they are really really slow at updating their apps to do HD. I know my Nexus 7 can't do HD either and pretty much all the videos look like crap on it.

It is a huge leap in back end resources needed to provide even 720 video let alone 1080 video over the current 480. Especially when you have a pretty large chunk (scientific measurement) using the Roku. You have to be prepared. I rather have an application that works than a HD one that might not work.